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Four Hour Temporal Relation of 5-HTP and L-DOPA Induces Inhibitory Responses in Recrudescing Gonad of Indian Palm Squirrel (Funambulus pennantii).

Jaiwal R, Chaturvedi CM - ISRN Endocrinol (2013)

Bottom Line: Other temporal relations (L-DOPA given at 0, 8, 12, 16, and 20 h after 5-HTP administration) did not show any effect on the recrudescing gonad.This inhibitory effect of 4 h was evident under short day length (6 : 18) group but was masked by the increasing day length of nature (NDL, late December onwards) and increased photoperiod of long day group (16 : 8).It is suggested that in spite of different environmental factors (photoperiod, humidity, etc.) used by different species to time their annual reproduction, basic mechanism of seasonality appears to be the same, that is, the temporal synergism of neurotransmitter activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, M. D. University, Rohtak 124001, India.

ABSTRACT
Daily injections of L-dihydroxyphenylalanine (L-DOPA, dopamine precursor) given 4 h after 5-hydroxytryptophan (5-HTP, serotonin precursor) induced inhibitory responses in recrudescing gonad (in the first week of December) of Indian palm squirrel, a seasonally breeding subtropical animal. Other temporal relations (L-DOPA given at 0, 8, 12, 16, and 20 h after 5-HTP administration) did not show any effect on the recrudescing gonad. This inhibitory effect of 4 h was evident under short day length (6 : 18) group but was masked by the increasing day length of nature (NDL, late December onwards) and increased photoperiod of long day group (16 : 8). It is apparent that seasonal testicular recrudescence of Indian palm squirrel during short day length by 4 h relation of 5-HTP and L-DOPA is not a pharmacological effect but actually is an alteration of seasonality in this annually breeding mammal. It seems that endogenous mechanism controlling seasonal testicular recrudescence of Indian palm squirrel is reset by timed daily injections of these neurotransmitter drugs. It is suggested that in spite of different environmental factors (photoperiod, humidity, etc.) used by different species to time their annual reproduction, basic mechanism of seasonality appears to be the same, that is, the temporal synergism of neurotransmitter activity.

No MeSH data available.


Related in: MedlinePlus

(a) T. S. of testis of NDL—control squirrel showing active condition. (b) T. S. of testis of NDL—4 h squirrel showing active condition. (c) T. S. of testis of LD 16 : 8—control squirrel showing full breeding condition. Bunched spermatozoa can be seen. (d) T. S. of testis of LD 16 : 8—4 h squirrel showing active condition. (e) T. S. of testis of LD 6: 18—control squirrel showing active condition. (f) T. S. of testis of LD 6 : 18—4 h squirrel showing inactive condition.
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fig1: (a) T. S. of testis of NDL—control squirrel showing active condition. (b) T. S. of testis of NDL—4 h squirrel showing active condition. (c) T. S. of testis of LD 16 : 8—control squirrel showing full breeding condition. Bunched spermatozoa can be seen. (d) T. S. of testis of LD 16 : 8—4 h squirrel showing active condition. (e) T. S. of testis of LD 6: 18—control squirrel showing active condition. (f) T. S. of testis of LD 6 : 18—4 h squirrel showing inactive condition.

Mentions: When compared to initial values, final testicular volume of squirrels of control as well as experimental subgroup increased significantly (Table 1). But when final value of NDL control and experimental squirrel were compared, testicular volume (Table 1), gonadosomatic index (GSI), and weight of accessory sex organs of 4 h treated squirrels were significantly less (Table 2). Histologically, testis of control squirrel showed full breeding condition with active spermatogenesis, while that of experimental group showed moderate activity but could not reach up to the extent of control testis (Figures 1(a) and 1(b)).


Four Hour Temporal Relation of 5-HTP and L-DOPA Induces Inhibitory Responses in Recrudescing Gonad of Indian Palm Squirrel (Funambulus pennantii).

Jaiwal R, Chaturvedi CM - ISRN Endocrinol (2013)

(a) T. S. of testis of NDL—control squirrel showing active condition. (b) T. S. of testis of NDL—4 h squirrel showing active condition. (c) T. S. of testis of LD 16 : 8—control squirrel showing full breeding condition. Bunched spermatozoa can be seen. (d) T. S. of testis of LD 16 : 8—4 h squirrel showing active condition. (e) T. S. of testis of LD 6: 18—control squirrel showing active condition. (f) T. S. of testis of LD 6 : 18—4 h squirrel showing inactive condition.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3713323&req=5

fig1: (a) T. S. of testis of NDL—control squirrel showing active condition. (b) T. S. of testis of NDL—4 h squirrel showing active condition. (c) T. S. of testis of LD 16 : 8—control squirrel showing full breeding condition. Bunched spermatozoa can be seen. (d) T. S. of testis of LD 16 : 8—4 h squirrel showing active condition. (e) T. S. of testis of LD 6: 18—control squirrel showing active condition. (f) T. S. of testis of LD 6 : 18—4 h squirrel showing inactive condition.
Mentions: When compared to initial values, final testicular volume of squirrels of control as well as experimental subgroup increased significantly (Table 1). But when final value of NDL control and experimental squirrel were compared, testicular volume (Table 1), gonadosomatic index (GSI), and weight of accessory sex organs of 4 h treated squirrels were significantly less (Table 2). Histologically, testis of control squirrel showed full breeding condition with active spermatogenesis, while that of experimental group showed moderate activity but could not reach up to the extent of control testis (Figures 1(a) and 1(b)).

Bottom Line: Other temporal relations (L-DOPA given at 0, 8, 12, 16, and 20 h after 5-HTP administration) did not show any effect on the recrudescing gonad.This inhibitory effect of 4 h was evident under short day length (6 : 18) group but was masked by the increasing day length of nature (NDL, late December onwards) and increased photoperiod of long day group (16 : 8).It is suggested that in spite of different environmental factors (photoperiod, humidity, etc.) used by different species to time their annual reproduction, basic mechanism of seasonality appears to be the same, that is, the temporal synergism of neurotransmitter activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, M. D. University, Rohtak 124001, India.

ABSTRACT
Daily injections of L-dihydroxyphenylalanine (L-DOPA, dopamine precursor) given 4 h after 5-hydroxytryptophan (5-HTP, serotonin precursor) induced inhibitory responses in recrudescing gonad (in the first week of December) of Indian palm squirrel, a seasonally breeding subtropical animal. Other temporal relations (L-DOPA given at 0, 8, 12, 16, and 20 h after 5-HTP administration) did not show any effect on the recrudescing gonad. This inhibitory effect of 4 h was evident under short day length (6 : 18) group but was masked by the increasing day length of nature (NDL, late December onwards) and increased photoperiod of long day group (16 : 8). It is apparent that seasonal testicular recrudescence of Indian palm squirrel during short day length by 4 h relation of 5-HTP and L-DOPA is not a pharmacological effect but actually is an alteration of seasonality in this annually breeding mammal. It seems that endogenous mechanism controlling seasonal testicular recrudescence of Indian palm squirrel is reset by timed daily injections of these neurotransmitter drugs. It is suggested that in spite of different environmental factors (photoperiod, humidity, etc.) used by different species to time their annual reproduction, basic mechanism of seasonality appears to be the same, that is, the temporal synergism of neurotransmitter activity.

No MeSH data available.


Related in: MedlinePlus